Sun Java Web Start and Java Plug-in for JDK and JRE 6 Update 10 and earlier; JDK and JRE 5.0 Update 16 and earlier; and SDK and JRE 1.4.2_18 and earlier allow remote attackers to execute arbitrary code via a crafted jnlp file that modifies the (1) java.home, (2) java.ext.dirs, or (3) user.home System Properties, aka "Java Web Start File Inclusion."

More... (http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2008-2086)